From the manual:
"Note that due to the way Construct 2 expressions work, if you have multiple Particle object instances, this will only return the particle count for one of the instances - use a For Each loop to count multiple instance's total particle count."
I have put my particle generators into a family so that I can use a For Each loop, and I have a text box that is set to count the total number of particles, but it's only showing me one instance. I've also tried using 'add' instead of 'set', and I just get an ever increasing number.
I know this should be pretty simple, but I just can't seem to get my head around it.